Flagger Operations: Investigating Their Effectiveness in Capturing Driver Attention


Kathleen Harder, John Hourdos

February 2017

Report no. MnDOT 2017-07



This two-pronged (driving simulation and field study) investigation of driver behavior in work zones contributes basic and applied knowledge to our understanding of work zone safety. In the driving simulator study, a fully interactive PC-based STISIM driving simulator was used to test the effectiveness of roadway elements designed to capture and sustain the attention of drivers in flagger-operated work zones. The participants were 160 licensed drivers from four age groups: 18-24, 32-47, 55-65, and 70+ years of age. Each participant drove each of the three conditions in counterbalanced order. The driving simulator study revealed that the new set of elements is more effective than the elements currently used to reduce driving speeds on the approach to a flagger-controlled work zone. No difference in mean driver speed was found in response to the sign with an LED presence. The dynamic speed display coupled with the horn is more effective than the dynamic speed display alone. The cognitively engaging elements identified as effective in the driving simulator study were tested in two field operational tests. The field tests revealed that all but one of the elements identified in the experimental driving simulator study were effective. In particular, the findings revealed that a combination of the speed trailer and horn barrel are effective in reducing the overall speed of vehicles approaching the field study work zone. The field test revealed that the new experimental layout practically eliminated high-speed outliers in addition to its success in reducing driver approach speed to the flag operator.

Download or order

Download PDF (6 MB)